Find the objects which are visible from current viewport using AutoCAD API C#

kite15 — Fri, 26 Nov 2021 12:59:50 GMT

Hi,

Can any one help to find the objects which are visible from the current viewport?

Since, my current layout name is "ABC" viewport id is "123456". Now, can I find the items which are completely in different list and partially in a different list, visible from from "ABC" layout and belongs from the viewport which have the id "123456"

Thanks and regards,

Re: Find the objects which are visible from current viewport using AutoCAD API C#

norman.yuan — Sat, 27 Nov 2021 15:17:28 GMT

Basically what you need to do is find the Viewport's boundary points (assuming it is regular rectangle, then 4 corner points) and calculate their projected points in ModelSpace with proper transformation (Matrix3d). As long as your get the projected rectangle/polygon in ModelSpace, you can test which entities are inside the rectangle/Polygon.

Here is a relevant discussion where you can find good code for getting a Matrix3d to transform coordinates from PaperSpace to ModelSpace, or the other way around:

http://www.theswamp.org/index.php?topic=34590.msg398539#msg398539

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Find the objects which are visible from current viewport using AutoCAD API C#

Re: Find the objects which are visible from current viewport using AutoCAD API C#